Cellular telecommunication presents unique signaling challenges, such as mobility and paging. To overcome these challenges, the generic Internet Protocol (IP) stack is augmented by GPRS (General Packet Radio Service) Tunneling Protocol (GTP) as used by Long Term Evolution (LTE) cellular networks. GTP version 1 uses User Datagram Protocol (UDP) for packet transmission over an IP link.
The user plane of LTE uses GTP tunnels for voice bearer and data bearer transmission. The GTP-U protocol is the variant of GTP used on the user plane. Typically, a separate GTP-U tunnel is used for each bearer channel. A GTP tunnel is identified by a conceptual triplet having the destination UDP address, the destination UDP port, and the Tunnel Endpoint Identifier (TEID) of the destination. GTP may multiplex tunnels onto one UDP pathway. A sequential pair of GTP-U tunnels is needed to provide bearer from an eNodeB through a servicing gateway (S-GW) and on to a PDN (Packet Data Network) Gateway (P-GW).
The Evolved Packet Core (EPC) is the core network of LTE. Within the EPC are a diversity of node types, such as S-GW, P-GW, and others. Each node type is dedicated to particular internal functions of the EPC. Regardless of type, nodes within the EPC may be virtualized as virtual network elements (VNE). A virtualization environment may have within itself a population of VNEs. A new VNE is dynamically added to the virtualization environment by instantiation. A surplus VNE is deleted from the virtualization environment by removal. Addition or deletion may also be achieved by migration between multiple virtualization environments.